HIGH-ACTIVITY ZIEGLER-NATTA CATALYSTS FOR THE PREPARATION OF ETHYLENE COPOLYMERS

High activity ethylene polymerization catalysts have been prepared by the interaction of ethylmagnesium chloride in tetrahydrofuran with high surface area silica, followed by reaction with excess titanium tetrachloride in heptane. The catalysts were tested in ethylene-hexene copolymerization reactions in the presence of AlEt//3 at 80 degree C. For comparison purposes, the copolymerization properties of a similar catalyst prepared without silica were also evaluated. The silica and the amount of magnesium used in catalyst preparation strongly affect the copolymerization properties of the catalysts.